Hilaire de chardonnet



UNITED STATES PATENT OFFICE.

HILAIRE DE OHARDONNET, OF BESANQON, FRANCE.

PROCESS OF DYEING ARTIFICIAL SILK.

n SPECIFICATION forming part of Letters Patent No. 410,404,dated September 3, 1889.

Application filed June 22, 1888. SerialNo. 277,895. (No specimens.) Patented in France January 27, 1888, No. 188,304, and in England April 9, 1888, No. 5,270.

To aZZ whom, it may concern.-

Be it known that I, HILAIRE DE CHARDON- NET, a citizen of the Republic of France, and a resident of Besancon, (Doubs,) France, have invented certain new and useful Improvements in the Art of Denitrating and Dyeing Artificial Silk and other Pyroxyline Substances, (which invention is the subject of Letters Patent in France No. 188,304, dated J anuary 27, 1888, and in England, No.5,270, dated April 9,1888,) of which the following is a specification.

When a pyroxyline in filaments or in sheets molded in different ways is digested in a bath containing certain reducing substances, as sugar, acetic acid, alcohol, protochloride of iron, &c., and when likewise pure water is employed, the pyroxyline is seen to gradually lose under the influence of time and temperature its combined nitrogen. Nitric acid produces the same effect in a more regular and complete manner. The action is increased by direct reason of the length of time, the concentration, and the temperature, which may Vary within wide limits, all leading to the desired result.

The process of denitration which I have invent-ed is the following: The pyroxyline is maintained at 30 to 35 centigrade in a bath of nitric acid of a density of about 1.32. In a few hours it loses a part of its nitrogen and descends beneath the tetranitric cellulose (Mr. Vieille.) This transformation is recognized either by an analysis or by a test of the solubility, or by observing at the beginning the softening which the pyroxyline undergoes. It is then washed rapidly with tepid or cold water, then dipped at this moment in the dyeing-bath, then washed with cold water, and dried in a current of tepid air.

This process applied to artificial silk (spun collodion) dispenses with the introduction into the mother solution of metallic chlorides and alkaloids, (designed to reduce the combustibility.)

The results which I have obtained lead me to the conclusion thatthe action is as follows:

The bath of nitric acid tends, according to its grees from zero up to seventy-five or eighty per centum, whether the combination is in definite proportions or not.

I give below a table of the results of an analysis of the reaction:

g gt 5 E g 5' kl q)! a s 3 5 a E a Time. a. jg "5g Egg 0 o a o 43" w w u a 55% an .2 5g 5g 5 E .0 0 Fr 0 5 no r: S a z: E s o E 2 Before the operation 90 113 435 At end of 1 hour 88 110 4% At end of 3 hours. 82 103 399 At end of 6 hours. 64 80 310 At end of 7 hours 55 G8 264 At end of 7% hours 63 244 I claim as my invention The process of dyeing artificial silk and other pyroXyline compounds, which consists in, first, denitrating the artificial silk or pyroxyline compound by immersion for a few hours in a bath of nitric acid; second, washing the den'itrated material, and, third, dipping the same in a dyeing-bath, substantially as set forth.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

IIILAIRE DE OHARDONNET.

Witnesses:

ROBT. M. HOOPER, AMAND RITTER. 

